import java.util.*;
public class Main {
    public static void main(String[] args) {
        System.out.println("Hello world!");
    }
    public List<Integer> findSubstring(String s, String[] words) {
        List<Integer> list=new ArrayList<>();
        int n=s.length();
        int m=words.length;
        int len=words[0].length();
        Map<String,Integer> hash1=new HashMap<>();
        for(String str:words){
            hash1.put(str,hash1.getOrDefault(str,0)+1);
        }
        for(int i=0;i<len;i++){
            Map<String,Integer> hash2=new HashMap<>();
            for(int left=i,right=i,count=0;right<=n-len;right+=len){
                String in=s.substring(right,right+len);
                hash2.put(in,hash2.getOrDefault(in,0)+1);
                if(hash2.get(in)<=hash1.getOrDefault(in,0)){
                    count++;
                }
                if(right-left+1>len*m){
                    String out=s.substring(left,left+len);
                    if(hash2.get(out)<=hash1.getOrDefault(out,0)){
                        count--;
                    }
                    hash2.put(out,hash2.get(out)-1);
                    left+=len;
                }
                if(count==m) list.add(left);
            }
        }
        return list;
    }
}